Student Nurses Guide to the Lungs (Respirations)

The lungs are located in the thoracic cavity; they are filled with spongy tissue filled with lymph vessels, alveoli, nerves and blood. The left long has an indentation to allow room for the heart; because of this the right lung has three lobes while the left lung has two lobes. The lungs are where gas exchange takes place.

Above the lungs is what is known as the bronchus. The right bronchus (where most aspirations take place) is larger in diameter and more vertical then the left. Each of the bronchus enters the lung at a notched area called the hilus or hilum. The small hairs in the bronchus are called cilia these drive out an impurities that try to enter the lungs by coughing, sneezing or by blowing your nose. The primary bronchus enters the hilum (hilus) and divides into subdivisions called bronchiole tree (the smallest being the bronchiole).

In the lungs blood passes through capillaries around the alveoli this is where gas exchange takes place. The alveoli are located at the terminal portion (end) of the bronchiole. These clusters of tiny sacs are where air exchange takes place. The walls of the alveoli are made up of a single layer of squamous epithelium tissue for easy passage of gases; the walls produce surfactant which is a substance that prevents alveoli from collapsing.

The lungs are covered by a double sac which is known as the pleura the inner layer of this sac is known as the visceral pleura and the outer layer is known as the parietal pleura. The area between the pleura is called the pleural space it holds a fluid that lubricates the membranes.

The process of respiration

Inhalation is the drawing of air into the lungs, this is considered active.

Exhalation is the expulsion of air out of the lungs, this is considered passive.

The amount of air that is moved in or out of the lungs in a quiet, relaxed breath (500ml) is called tidal volume.

Volume of air that remains in the lungs after maximum exhalation (1200ml) is the residual volume.

Total lung capacity is the total volume of air contained in the lungs after maximum inhalation (6000ml).

Vital capacity is the volume of air that can be expelled from the lungs by maximum exhalation after maximum inhalation (4800ml).

Breathing room air is equal to 20% oxygen. The gas is exchanged through diffusion at a higher to lesser concentration while carbon dioxide leaves the body through diffusion as well.